Induction of gene expression of antibacterial proteins by chitin oligomersin the silkworm, Bombyx mori

Activation of antibacterial protein genes by various chitin oligomers (from dimer to hexamer) was investigated by Northern blot analysis using cDNAs e ncoding cecropin B, attacin and lebocin from Bombyx mori as probes. Ail chi tin oligomers tested were found to strongly trigger expression of cecropin B, attacin and lebocin genes. Furthermore, gene expression triggered by chi tin oligomers was confirmed to occur specifically in the fat body and haemo cytes. These results suggest that chitin oligomers have the same characteri stics as those of lipopolysaccharide (LPS) and peptidoglycan in triggering gene expression of insect antibacterial proteins.